1. Field of the Invention
The invention concerns plasma processing apparatus and, more precisely, it concerns chemical vapor deposition apparatus (CVD apparatus) with which dielectric films are deposited on substrates using plasma in the manufacturing process of semiconductor devices.
2. Description of Related Art
Plasma-enhanced chemical vapor deposition apparatus (PECVD apparatus), with which dielectric films are deposited with plasma assist, are used in the semiconductor device manufacturing process. Diode parallel plate PECVD is often used for the CVD apparatus. High density plasma (HDP) is required for dielectric film gap-fill for a design rule of .ltoreq.0.25 .mu.m in ultra-large integrated circuits with apparatus of this type.
Conventional HDP-PECVD apparatus with which dielectric films are deposited has been disclosed, for example, in Japanese Unexamined Patent Publication H8-92748 and Japanese Unexamined Patent Publication H8-213196. All of the literature discloses inductively coupled plasma (ICP) sources in which a coil is used. HDP-PECVD apparatus in which an ICP source is used must have at least the side wall of the reactor made of a dielectric material such as quartz glass since the induced electric field is introduced into the plasma generating space from a coil which is wound externally on the reactor.
Conventional HDP-PECVD apparatus have a dielectric material as the side wall of the reactor, as mentioned above, and so the two problems indicated below arise. The first problem is that the side wall of the reactor deteriorates because plasma cleaning is carried out repeatedly. The second problem is that it is difficult to establish a shower-type reaction gas delivery inlet port or a plurality of inlet ports in the upper part of the reactor from a safety viewpoint. A nozzle-type reaction gas delivery inlet port or a single inlet port is used in the aforementioned patent specifications.
These problems become more pronounced when the reactor must be increased in size in line with the diameter of the substrate which is to be processed.